The invention relates to an apparatus for pumping effluents from a well or a cluster of wells and for boosting their pressure in order to transfer them to a process facility.
The invention relates more in particular to a pumping apparatus comprising a fluid motor and a rotary pump driven thereby. Fluid driven pumps of this type may be employed to produce hydrocarbons in their natural form from oil fields. These hydrocarbons may contain crude oil, natural gas, water and some solids like sand and salt.
The varying composition and gas content of the pumped well effluents make pumping difficult and it is known from U.S. Pat. No. 2,470,878 and from European patent application No. 87400158.9 (publication No. 0236166, publication date: 9th September, 1987) that it may be advantageous to mix some of the driving liquid with the well effluents in order to increase the liquid content thereof. In view of the harsh operating conditions regular maintenance and inspection of the pumping equipment is required.
If the pump forms part of a pump station at a remote location such as at a subsea wellhead, retrieval of the pump for maintenance or inspection may be a cumbersome and difficult operation.